Tappet assembly lubricating means

ABSTRACT

A reciprocating mechanism includes a roller which cooperates with a cam to effect reciprocation of a plunger. The roller is mounted on a pin and for the purpose of lubrication, the plunger is provided with a piston which is moved in a cylinder during reciprocation of the plunger. The cylinder is connected by a passage to the bearing defined between the pin and the roller and oil is forced along the passage by the piston to lubricate the bearing, during inward movement of the plunger under the action of the cam.

lllnilenl Sites ntent Inventor Ronnltl Phillips Northnlt, Middlesex, England Appl; No. 8,994 Filed lFeh. 5, 11970 Patented Dec. 21, 11971 Assignee Simms Group Research & Development Limited London, England Priority llelm. 117, 1969 Great Britain 8,436/69 TAPPET ASSEMBLY LUBRICATING MEANS 2 tllaims, 11 Drawing Fig.

11.8. C1 l84/6.l7, 184/628 lnt. C1 F1611 113/14 Field oi Search 184/6, 6 N,

[56] References Cited UNITED STATES PATENTS 1,672,360 6/ 1928 Whitehead 184/6 Y 2,056,901 10/1936 Kylen 184/6 N 2,754,814 7/1956 l-lopwood 184/6 Y 3,396,819 8/1968 Baxter et 184/6N 3,498,273 3/1970 llumphreys 184/6 X Primary Examiner-Manuel A. Antonakas Attorney-Holman dz Stern ABSTRACT: A reciprocating mechanism includes a roller which cooperates with a cam to effect reciprocation of a plunger. The roller is mounted on a pin and for the purpose of lubrication, the plunger is provided with a piston which is moved in a cylinder during reciprocation of the plunger. The cylinder is connected by a passage to the bearing defined between the pin and the roller and oil is forced nlong the passage by the piston to lubricate the beating, durinp, inward movement of the plunger under the action of the cam.

PATENTEUBEENBTI 35281529 ATTORNEYS This invention relates to reciprocating mechanisms of the kind comprising a reciprocable plunger and a tappet assembly including a roller mounted upon a pin, the roller being arranged to bear upon the surface of a cam whereby as the cam rotates axial movement will be imparted to the tappet assembly and plunger.

When such mechanism is operated at high speed it has been found that there is a risk that the roller will seize upon the pin and this rislt is not substantially minimized by immersing the tappet assembly in lubricant. It is therefore an object of the invention to provide such a mechanism in a form in which the risk of seizure is minimized.

According to the invention a mechanism of the kind specified is characterized in that there is associated with the plunger, a piston portion which cooperates with the wall of a cylinder defined about the plunger and which during movement of the tappet assembly and plunger away from the axis of rotation of the cam displaces lubricant under pressure to the cooperating surfaces of the roller and pin.

One example of a mechanism in accordance with the invention will now be described with reference to the accompanying drawing which is a sectional side elevation of the mechanism.

With reference to the drawing there is provided a plunger 7 which is slidably accommodated in a bore 17 formed in a sleeve like member 18 mounted within a body part. The plunger extends from the bore 17 and the free end of the plunger is provided with an abutment 4 against which bears a spring abutment 19 against which is located at one end of a coiled compression spring acting to urge the plunger outwardly.

Also provided is a tappct assembly which comprises a cupshaped member 3 having a cylindrical outer surface and also having an aperture formed in its base wall. The member 3 is slidable within a suitable aperture formed in the body part a portion of which is seen at 20. The spring abutment 19 bears upon the open end of the member 3 and transversely disposed within the member is a bearing pin 5. Rotatably mounted upon the bearing pin is a roller assembly which includes a sleeve 6 about which is mounted a roller portion 21. The roller portion projects through the aperture in the base wall of the member 3, into contact with the surface of a rotary earn 2 mounted upon a rotary shaft ll, Located within the cup-shaped member 3 is a thrust piece 22 having leg portions which cooperate with portions of the pin 5 on opposite sides of the roller. Moreover, the upper surface of the thrust piece bears against the end of the plunger 7 and in this manner the thrust generated by the cam 2 is transmitted to the plunger 7. in order to secure the member 3 to the thrust piece 22 the latter is provided with a circlip.

in operation during rotation of the cam the tappet assembly and the plunger are moved away from the axis of rotation of the cam and are returned by the action of the spring.

In order to provide lubrication of the bearing surfaces of the roller and pin the mechanism is immersed in lubricant up to the level indicated at 116. Moreover, the bearing surfaces are supplied with lubricant under pressure as will now be described.

The bore 17 is enlarged at its end and defines with the plunger an annular cylinder in which is mounted an annular piston portion The piston portion is slidable relative to the plunger between a shoulder defined on the plunger and an abutment defined by a ring 9 secured to the plunger by means of a circlip M).

The piston portion has three equiangularly inwardly extending projections which cooperate with the plunger and disposed between the projections are axial spaces ill. When the piston portion is located against the shoulder as shown in the drawing, the spaces 11 are open to the annular chamber by virtue that at their upper ends the spaces flare outwardly. When the piston portion is located against the ring 9 the spaces are closed at the lower ends. The piston portion together with the ring constitute a valve means for controlling ubncant flow into the cylinder.

Formed in the plunger is a transverse drilling 13 which at its ends communicates with the cylinder and which communicates with an axial drilling 12 in the plungerv Moreover, formed in the thrust piece 22 is a passage M which communicates with the passage 12 and which also communicates with a feed groove 15 formed on the bearing pin. In use, during movement of the plunger 7 under the influence of the spring the piston portion is in the position shown and lubricant is drawn into the chamber by way of the spaces ill. During the initial movement of the plunger under the action of the cam, the piston 8 remains still and the spaces 11 are sealed by the ring 9. Thereafter continued movement of the plunger displaces lubricant along the passages 13, 112, 14 to the feed groove 15 thereby ensuring lubrication of the bearing surfaces of the pin and roller.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A reciprocating mechanism of the kind comprising a reciprocable plunger and a tappet assembly including a roller and a pin mounting the roller on a tappet body, an annular member located about the plunger and movable a limited axial extend elative thereto, said annular member acting as a piston, a cylinder in which said piston is slidable, a ring mounted about the plunger, said ring together with the piston constituting a valve means for controlling the flow of lubricant into the cylinder and passage means through which lubricant can flow from the cylinder to lubricate the pine and roller.

2. A mechanism as claimed in claim 1 including a plurality of axial grooves formed in the inner peripheral surface of said piston, said grooves being on constant communication with said cylinder, the grooves being closed by said ring during movement of the plunger by the cam to efi'ect discharge of lubricant along said passage.

i t l i ii 

1. A reciprocating mechanism of the kind comprising a reciprocable plunger and a tappet assembly including a roller and a pin mounting the roller on a tappet body, an annular member located about the plunger and movable a limited axial extend elative thereto, said annular member acting as a piston, a cylinder in which said piston is slidable, a ring mounted about the plunger, said ring together with the piston constituting a valve means for controlling the flow of lubricant into the cylinder and passage means through which lubricant can flow from the cylinder to lubricate the pine and roller.
 2. A mechanism as claimed in claim 1 including a plurality of axial grooves formed in the inner peripheral surface of said piston, said grooves being on constant communication with said cylinder, the grooves being closed by said ring during movement of the plunger by the cam to effect discharge of lubricant along said passage. 